"US President Trump's recent giant military contracts which Gulf monarchies raise the risk of a new spiral in arms sales," Gabriel warned in an interview with the Handelsblatt daily to appear on Wednesday.

"This policy is completely wrong and is certainly not Germany's policy," he added, in extracts of his interview released Tuesday. "I am very concerned with the dramatic escalation and the consequences for the whole region."

Trump on Tuesday backed the regional efforts to isolate Qatar, supporting Saudi Arabia and its allies and suggesting the key US ally - home to the largest American airbase in the Middle East - has been funding "extremism".

During his recent visit to Saudi Arabia, Trump signed arms contracts worth $110bn with Riyadh.

Gabriel warned against completely isolating Qatar and said the move is an attack on the Gulf state's very existence.

"Apparently, Qatar is to be isolated more or less completely and hit existentially. Such a 'Trumpification' of relations in a region already susceptible to crises is particularly dangerous," Gabriel said.

He added the nuclear deal agreed with Iran in 2015 had allowed just such an escalation to be avoided.

"A toxic conflict between neighbours is that last thing we need," Gabriel warned.

He will meet his Saudi counterpart Adel al-Jubeir in Berlin on Wednesday.